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I/O Code Practice

2022-07-29 15:35:00 【51CTO】

       
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I/O代码实践_打印流

打印流分为PrintStream 和PrintWriter

     PrintStream :In view of the byte 调用println Content of a newline, etc 自动调用flush方法(Automatically send the contents of the buffer to a file)
PrintWriter:针对字符只有在调用println 才会自动调用flush方法(Automatically send the contents of the buffer to a file)

       
       //System.out.println() 打印到屏幕（标准输出设备） 建立在 PrintStream基础上
       
       File 
       
       file
       
       =
       
       new 
       
       File(
       
       "d:/aa/1.txt");
       
       try {
       
       PrintWriter 
       
       printWriter
       
       =
       
       new 
       
       PrintWriter(
       
       file);
       
       printWriter.
       
       println(
       
       "hello");
       
       printWriter.
       
       println(
       
       "world");
       
       printWriter.
       
       close();
       
        } 
       
       catch (
       
       FileNotFoundException 
       
       e) {
       
       // TODO Auto-generated catch block
       
       e.
       
       printStackTrace();
       
        }
       
       String 
       
       filename
       
       =
       
       FilenameUtils.
       
       getName(
       
       "d:/aa/1.txt"); 
       
       //返回文件名
       
       System.
       
       out.
       
       println(
       
       filename);
       
       String 
       
       extname
       
       =
       
       FilenameUtils.
       
       getExtension(
       
       "d:/aa/1.txt"); 
       
       //返回文件的扩展名(后缀名)
       
       System.
       
       out.
       
       println(
       
       extname);
       
       System.
       
       out.
       
       println(
       
       FilenameUtils.
       
       isExtension(
       
       "d:/aa/0.jpg", 
       
       "jpg"));
       
       //判断文件后缀名
       
       long 
       
       begin
       
       =
       
       System.
       
       currentTimeMillis();
       
       try {
       
       FileUtils.
       
       copyFile(
       
       new 
       
       File(
       
       "d:/aa/0.jpg"), 
       
       new 
       
       File(
       
       "d:/aa/1.jpg"));
       
    } 
       
       catch (
       
       IOException 
       
       e) {
       
       // TODO Auto-generated catch block
       
       e.
       
       printStackTrace();
       
    }
       
       long 
       
       end
       
       =
       
       System.
       
       currentTimeMillis();
       
       System.
       
       out.
       
       println(
       
       "With the toolkit copy file unavailable:"
       
       +(
       
       end
       
       -
       
       begin)
       
       +
       
       "毫秒");
      
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I/O代码实践_配置文件_02

properties

PropertiesIs an attribute class,Perhaps it may rarely use in some junior project,但是Properties文件,In many projects often can use,It makes our configuration properties of retrieval,Convenient project configuration properties change of the late.

       
       //属性类 是一个集合 实现的是map接口
       
       Properties 
       
       properties
       
       =
       
       new 
       
       Properties();
       
       //存数据
       
       properties.
       
       put(
       
       "type", 
       
       "mysql");
       
       properties.
       
       setProperty(
       
       "dbname", 
       
       "taobao");
       
       properties.
       
       setProperty(
       
       "uid", 
       
       "mayun");
       
       //获取属性信息
       
       //System.out.println(properties.getProperty("uid"));
       
       //To save the information in the collection to the file
       
       File 
       
       file
       
       =
       
       new 
       
       File(
       
       "db.properties");
       
       FileWriter 
       
       fileWriter;
       
       try {
       
       fileWriter 
       
       = 
       
       new 
       
       FileWriter(
       
       file);
       
       //In the collection data saved to a stream
       
       properties.
       
       store(
       
       fileWriter, 
       
       "info");
       
       fileWriter.
       
       close();
       
    } 
       
       catch (
       
       IOException 
       
       e) {
       
       // TODO Auto-generated catch block
      
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I/O代码实践_配置文件_03

       
       Properties 
       
       properties
       
       =
       
       new 
       
       Properties();
       
       try {
       
       //The default path is the root directory of the current project
       
       FileReader 
       
       fileReader
       
       =
       
       new 
       
       FileReader(
       
       "db.properties");
       
       properties.
       
       load(
       
       fileReader);
       
       System.
       
       out.
       
       println(
       
       properties.
       
       getProperty(
       
       "uid"));
       
        } 
       
       catch (
       
       FileNotFoundException 
       
       e) {
       
       // TODO Auto-generated catch block
       
       e.
       
       printStackTrace();
       
        } 
       
       catch (
       
       IOException 
       
       e) {
       
       // TODO Auto-generated catch block
       
       e.
       
       printStackTrace();
       
        }
      
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更多了解

https://edu.51cto.com/course/20124.html

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版权声明
本文为[51CTO]所创，转载请带上原文链接，感谢
https://yzsam.com/2022/210/202207291450204740.html

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